The research proposed in this supplementary application is a continuation and reinforcemnt of ongoing work on the general subject of Information channeling in the retina. Particular attention is being paid to the ways in which different parameters of the input stimuli are descriminated and then used to relate the organism to its visual world. Several kinds of preparations have been used to advance our understanding of this field. For example, the relation of fine structure to e-vector discrimination has been studied by us in rhabdom bearing eyes. The molecular and cellular basis for perceiving the orientation of the polarization plane was determined in this phase of the work. In addition our electron microscope technique of demonstrating this revealed widespread changes in photoreceptor cell fine structure in relation to its sensory activity. In turn this raised important points relevant to the turnover of the photoreceptor membrane as normal visual function is maintained. Both electrophysiological and EM techniques have been applied to analyzing the relationship between e- vector sensing input channels (2 types) and the color discriminating channels (2 types) in the crayfish retina. We are planning to continue this work both as a marker for identifying the cellular participants in a given receptive process and as a contribution to our understanding of the membrane function involved in it. We are currently tracing the appearance of acid phosphatase in the lysosome like bodies retinular cells as well as using molecular tracers (like myoglobin) to demonstrate directly whehter pinocytotic vesicles formed by receptor membrane are incorporated in the lysosomes and then removed from the receptor area. An important and somewhat unexpected step in our recent work has been the demonstration of e-vector sensitivity in the vertebrate eye. Behavioral, optical and electrophysiological techniques are being applied to this study.